| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 12 |
| 3 | 82 |
| 4 | 469 |
| 5 | 2502 |
| 6 | 12966 |
| 7 | 66325 |
| 8 | 337222 |
| 9 | 1709652 |
| 10 | 8655795 |
| 11 | 43794966 |
| 12 | 221516992 |
| 13 | 1120277983 |
| 14 | 5665183308 |
| 15 | 28647552996 |
| 16 | 144861882889 |
| 17 | 732516467528 |
| 18 | 3704069018506 |
| 19 | 18730095418683 |
| 20 | 94711027286382 |
| 21 | 478917748054834 |
[1,12,82,469,2502,12966,66325,337222,1709652, 8655795,43794966,221516992,1120277983,5665183308, 28647552996,144861882889,732516467528, 3704069018506,18730095418683,94711027286382, 478917748054834] |